<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <!--style标签专门用来定义css样式代码-->
    <!--<style type="text/css">
         /*需求1：分别定义两个 div、span标签，分别修改每个 div 标签的样式为：边框1个像素，实线，红色。*/
        div {
            border: 1px solid green;
        }
        span {
            border: 1px solid red;
        }
    </style>-->

    <!--link标签专门用来引入css样式代码-->
    <link rel="stylesheet" type="text/css" href="1.css"/>
</head>

<body>
<div>div标签1</div>
<div>div标签2</div>

<span>span标签1</span>
<span>span标签2</span>
</body>
</html>